Telephone system.



A. H. DYSON.

TELEPHONE SYSTEM.

APPLICATlON FILED DEC-20, 1905.

1 l @%@3& Patented. May 30, 1916.

5 SHEETS-SHEET 1.

6:12? n wy l A. H. DYSON.

TELEPHONE SYSTEM.

APPLICATION FILED DEC.20 1905.

Patented May 30,1916.

5 SHEETS-SHEET 2- A. H. DYSON.

TELEPHONE SYSTEM.

APPLICATION FILED DEc.20. 1905.

Patented May 30, 1916.

5 SHEETS-SHEET 3.

wmw

A. H. DYSON.

TELEPHONE SYSTEM.

APPLICATION FILED 050.20. 1905.

A. H. DYSON.

TELEPHONE SYSTEM.

APPLICATION FILED DEC-20, I905.

1 1 @%@3& Patented May 30, 1916.

5 SHEETS-SHEET 5 orrioia.

ALFRED H. DYSON, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNJE ASSIGNMENTS,TO KELLOGG SWITGHJBOARD & SUPPLY COMPANY, A CORPORATION OF ILLINOIS.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Application filed December 20, 1905. Serial No. 292,597.

To all whom it may concern Be it known that I, ALFRED H. DYSON, acitizen of the United States, residing at Chicago, county of Cook, andState of Illinois, have invented new and useful Improve: ments in-Telephone Systems, of which the following is a specification.

My invention relates to telephone systems in which visual signals areemployed to notify operators in regard to the condition of subscriberslines.

The object of my invention is to provide improved signaling means andarrangements of apparatus forsuch systems.

I provide a switchboard having springjacks for subscribers lines,together with single plug-cords for making connection! therewith. Idispense with the other plug usually employed, and terminate the otherend of the link-circuit in switching contacts of a traveling switch.Such a switch may comprise movable contactarms and a plurality ofswitching contacts, forming switching terminals of link-circuitsdescribed above. The calling subscriber first causes the movablecontact-arms to engage switch ing contacts, terminals of a firstlink-circuit. These terminals are multipled to other traveling switches,and if the link-circuit connected with the first terminals is already inuse, a series of local circuits are set up independent of thesubscriber, whereby the movable arms move over busy terminals until theyreach the first idle ones, when their motion is arrested. When thisoccurs, a signal in front of the operator is caused to be displayed andthe operator listens in, ascertains the number of the desired subscriberand completes the connection with the plug forming the terminal of theselected linkcircuit. She then rings the called subscriber in the usualmanner. Double supervision is provided for each cord-circuit inconsonance with the usual practice in telephone switchboards of the mostapproved character.

For the purpose of preventing interference with existing connectionswhen the linewipers of a switch are moving over terminals of busycord-circuits, I preferably arrange the traveling switch structure insuch a manner that the said wipers are disconnected from the callingline and, in fact, on entirely open circuits in the switch while movingover busy contacts and I provide means for instantaneously connectingthem with the calling line as soon as the switch comes to rest inengagement with an idle l nk or trunk-circuit. I also provide means forrestoring to normal the switch when conversation ends, or at any othertime under control of the calling subscriber.

My invention is equally adapted to multiple swltch-board structures, aswell as to non-multiple boards, as will be apparent in the followingdescription.

A valuable feature of my invention is found in its adaptability to beemployed for the purpose of providing connection between automatictelephone exchange subscribers hues and manually operated telephoneexchange subscribers lines. It is, however, my desire not to be limitedto this employment of my invention, as my invention is broader than thisnarrow application of it.

In the accompanying drawings, I show various applications of myinvention, not limited to the narrower application thus brieflydescribed.

Figure 1, consisting of Sheets 1 and 2, illustrates the circuitarrangement of a telephone exchange system, arranged in accordance withone application of my invention. Fig. 2 illustrates a link-circuitterminating in a single plug and an associated telephone circuit of wellknown character. Fig. 3 illustrates a varying form of link-circuit,adapted to make connection with an automatic line. Fig. 4 illustratestwo substations connected by their lines with automatic switches and alink-circuit terminating in a single plug for interconnecting them. Fig.5 illustrates a selector switch. Fig. 5 is a plan view of a primarymagnet, its armature and associated mechanism. Fig. 6 is a view inperspective of a side-switch pawl and its mechanism. Fig. 7 is a sideview of a primary magnet. Fig. 8' is a side view of a secondary magnet.Fig. 9 illustrates a connector switch release magnet and its associatedparts. Fig. 10 shows the relative normal positions of wipers andcontact-levels when switch 5 is adjusted for circuit Fig. 4. Fig. 11shows an off-normal switch combination for rotary motion only. Figs. 5to 9 show all the mechanical combinations required for the variouscircuits, other than ordinary relay combinations, andwill, therefore, befirst described. The switch,- shown in these figures, I do not claim asmy invention.

hereafter Referring first to Fig. 5, in the lower ortion of said figureI have shown two banks of insulated contacts, those of the upper bankbeing arranged in pairs and those of the lower bank being singlecontacts. These contacts are terminals of electrical conductors arrangedin sets of three, any pair of contacts in the upper bank andacorrespondingly located single contact in the lower bank constituting aset, each set forming connecting terminals of a trunkcircuit. Associatedwith the upper bank are wipers 51 and 52, and with the lower bank iswiper 50. Horizontally, the banks are concave, the arrangement beingsuch that when shaft 150, to which the Wipers are attached, insulatedone from the other, is

raised upward, the wiper select a row; and

when the shaft, having been raised, is rotated, the extremities of thewipers engage successive sets of contacts of selected rows. Upon theupper portion of the shaft are provided two ratchets, the upper onebeing adapted to be engaged by awl 31, its teeth being disposedhorizontal y, and the lower one by pawl 25", its teeth being disposed upand down. In Figs. 7 and 8 are illustrated the details of theseratchets, the pawls and the magnets controlling them.

Referring to Fig. 5, the lifting movement of the shaft is secured bymeans of current impulses caused to flow through magnet 31. The first ofthese causes pawl 31 to engage the upmost tooth of its ratchet and liftthe shaft one step upward. At the same time, arm 31', part of themagnets armature, lifts arm 32 to disengage detent 32, which movestoward the shaft and with its upper portion engages the tooth of theratchet next below that upon which pawl 31 acted, and holds the shaft inthe raised position. With the first energization of magnet 31, arm 31,part of its armature, lifted arm 34 out of engagement with the pin uponarmature 32 and the armature falls backward so that its pin no longerengages the. off-set in arm 34. This releases side-switch pawl 34preparatory to its actuation, as

described. Successive current impulses, sent through magnet 31, causethe shaft to be'lifted successive steps, each step bringing wipers 51,52 and 50 on a level with different horizontal rows of contacts, detent32 engaging successive horizontal teeth and holding the shaft in itsraised position after each step. Contact-levels having been selected,the shaft 150 is caused to be rotated by current impulses sent throughmagnet 25. Each impulse causes it to attract itsarmature 25 to which isattached pawl 25*, which thereupon moves the shaft a step in a rotaryclockwise direction. by engaging its associated ratchet. The lowerportion of detent 32 en ages successlvely the vertically dispose ratchet-ture 30 of magnet 29.

teeth of the shaft and holds the shaft in its rotated position aftereach thrust of pawl 25*. A stationary detent 32' is provided whichengages the ratchet shown associated with it with the first rotarymovement of the shaft. While the shaft is being lifted, this detent isin the slot 32 shown in Fig. 7, so that it does not prevent the liftingmovement of the shaft.' Each rotary step of the shaft causes the Wipersto engage successive sets of contacts.

Referring now to private magnet 29, when its armature 30 is attracted,ratchet 30, attached thereto, is moved downward with respect toside-switch pawl 34, so that the extremity of the pawl leaves tooth cand engages tooth c, this motion being too little to alter contactbetween arm 34'and contact 35. When, now, the magnet is denergized, pawl3 1 slips down and engages tooth b. Pawl 34: being pivoted as shown, andarm 34 being attached to said pawl, this movement causes the arm to disengage contact-point 35 and to engage contact-point 36. A second enerization and denergization of magnet 29 will cause pawl 34* to move intoengagement with tooth a by a similar operation, and arm 34 to move toengage contact-point 37. An arm 25, attached to armature 25, extends toarma- This arm would, when magnet 25 is energized and denergized,eflFect the circuit changes described in connection with pawl134", ifmagnet 29 "should remain deenergized, by thrusting in and allowing theretraction of armature 30 each time magnet 25 is energized. Shouldmagnet 29 be energized, as long as it con-- tinues so, obviously nomovement of its armature, under the influence of arm 25, is possible.This arm is provided for the purpose of causing pawl 34 to engage tootha, if the first contacts of selected levels are idle when engaged by thewipers, as will be more fully understood when the circuits aredescribed.

In Fig. 6, I show associated with pawl 34* a plurality of circuitchanging arms and associated contact-points for them to engage,illustrating the manner in which each movement of pawl 34 may beemployed to effect a plurality of simultaneous circuit changes.

The return to normal of the switch shown in Fig. 5 is effected by theenergization and denergization of magnet 32; When the magnet isenergized, it attracts armature 32, which moves arm 32 toward the shaft,the said arm engaging with the tooth at its extremity the pin shownassociated with detent 32. The pin associated with armature 32 moves tosuch position that it again engages the off-set in arm 34". en magnet 32is deenergized, its armature is retracted and moves arm 34" to the rightand with it maaeaa 11a:

pawl 34 to again engage tooth 0 so that the side-switch returns tonormal. When the armature is retracted, arm 32 withdraws detent 32 fromits engagement with the ratchets of the shaft. The rotation of the shaftis effected against the torsion of spring 151, and the shaft, being nowfree, is rotated counter clockwise until the wipers are beyond thelefthand or first contacts of the selected rows. Whenthis occurs,stationary detent 32 has reached the slot in the ratchet shown in Fig.7, and the shaft descends by gravity, aided by spring 151, to theposition shown.

The structure above described is that employed in connection with theselector switch circuits shown at D and Cr in Fig. 1. Substantially thesame switch may be employed in connection with the connector switchcircuits shown at E in Fig. 1. When thus employed however, the arm 25 isomitted. For certain operating reasons, it is-preferable to release theconnector switch with the forward stroke of its release magnetsarmature. In Fig. 9, I show a connector switch release magnet 32 and itsassociated mechanism. In the said figure, 31", part of the primarymagnets armature, with the first energization of said magnet, lifts arm32 to disengage the pin upon de tent 32 which thereupon moves forwardand engages the shaft as described. Sideswitch pawl 34? is normally, asshown, free to move, and arm 31, shown in Fig. 5, is

not required. When release magnet 32 is energized and attracts itsarmature 32", arm 34, attached to the said armature, moves from left toright and, with its right extremity, restores side-switch pawl 34, andwith the hook upon its left extremity withdraws the detent fromengagement with the shaft ratchets, the shaft thereupon returning tonormal as described. As the differences between the selector switch andthe connector switch are so slight, I have deemed it preferable toillustrate such variations as exist by themselves rather than encumberthe specification with additional drawings which would be substantiallyduplications of Figs. 5 to 8.

As is well known, two kinds of telephone exchange switchboards, widelydifiering in character, are in use in this country; namely, first, whatare ordinarily called manual switchboards, in the employment of whichthe various connections are completed by telephone operators; andsecondly, what are called automatic switchboards, in whose employmentconnections are established by means of step-by-step switches operatedand directed by subscribers, no operators being employed at theexchange. It has become usual to refer to lines terminating in boards ofthe first character as manual lines, and to the associated subscribersas manual subscribers. Conversely, automatic lines and automaticsubscribers are commonly employed terms, and these terms will forconvenience be employed in the specification.

Referring now to Fig. 1, consisting of Sheets 1 and 2, I show automatictelephone -ing two lines automatically, or without the intervention of atelephone operator. The apparatus above described I do"not claim as myinvention. At B, I illustrate a third substation connected, by itstelephone line, with its line circuit at the exchange including theusual line signal for attracting an opera-tors" attention, together withsuitable relay combinations for controlling the signal. This structureis well known in the art, is in extended commercial use and need not bedescribed in detail. At H, I have illustrated a link-circuit terminatingat one end in contacts 58, 54 and 55, forming stationary contacts of aselector switch, and at the other end in. contacts 89 and 90 of amanually operated plug. Contacts 53, 54 and 55' represent multiples atanother selector switch. This circuit II also ,cornprises signalingdevices associated with its end terminating in the plug, of a characterhereafter described. This circuit is for use in interconnectingautomatic lines with manual lines, and I claim the same as myinventionby itself and in combination. At F, I show another link-circuit, which Ialso claim as my invention, as in the case of circuit I-I. Circuit F isadapted to be used in connecting a manual line with an automatic linewhen the manual subscriber is the originator of the call. It is alsoemployed in cases where an automatic subscriber has connected his linewith circuit II, when desiring connection with another automaticline, incompleting the call 'directly to the desired automatic line by manualmeans.

In Fig. 1, I have shown two batteries 33 and 76. The former appears atvarious positions in the drawing, being shown'thus to avoid confusion.This is the battery employed in connection with automatic exchangeapparatus, and in practice it'is'ordinarily a fifty-volt battery. Theother battery 7 6 is employed in connection with the manual exchange andin practice is ordinarily a twenty-four-volt battery. Two batteries are,however, not necessary. Referring now to Fig. 1, the operation of theautomatic telephone system shown therein will be briefly described, itbeing well leases it. As long known in the art and having gone intoextensive commercial use.

Connection from an automatic line to an automatic nection, circuits A,D, E, G and C only, are brought into use. The system as shown is adaptedfor use in an exchange numbering about one thousand subscribers; For alarger exchange, second selector switches would be employed, of acharacter and arran ement well known in the art. Each subscri ers linewould be provided with a selector switch, as D, comprising wipers andtheir associated banks of one hundred sets of contacts, as shown in Fig.5.

Certain of the different contact-levels of the banks would be comprisedof terminals of connector switches, the contact sets of each of saidlevels being terminals oftrunk lines leading 'or connection to aparticular one hundred lines. Each connector swltch includes wipers andmultiple contacts, terminals of one hundred subscribers lines.

A subscriber, desiring to connect his line with another line, firstcauses the wipers of his selector switch to select the proper level ofconnector switch terminals. The selector switch then automaticallyselects the terminals of the first idle connector switch. The subscriberthen causes the connector switch wipers to select multiple terminals ofthe desired line, which will be included in its banks, thus completingthe connection.

In placing reference characters upon the connector switch circuits shownat E, I have supplied the same numbers to the operating magnets andside-switch parts'as those supplied in Fig. 5, adding to the numbers adistmguishing letter y. By this means, reference may be readily made tothe mechanical drawing, when description of theconnector switch circuitis given.

Assuming that the subscriber, whose substation is illustrated at A,desires tobe connected with the subscriber at the automatic exchangewhose number is assumed to be 627, whose substation is shown at C, hefirst removes his receiver from the hook, the hook-lever moving upward,closingcontact 8-9 and connecting contacts 10 and 11, thus closing thesubstation transmitter circuit. He then rotates dial Z from left toright until six teeth have passed below spring 5, and reas the dial isin other than normal position, contact 6-7 is open. The dial returns tonormal and in so doing closes and opens contact between springs 5,

and 4 six times. Each closure causes an impulse of current to flow fromground G, through contacts 4-5, 9-8, limb P, 42-43, relay 20 to battery33. Relay 20 is energized and deenergi'zed. six times, attracting itsarmature each time and causing current to flow from ground Gflthroughcontact 23-22,

line: In making an automatic conto connector switches assignedthesecircumstances.

armature 30, primary magnet 31 to battery 33. Associated with wipers50,51 and 52, are contact banks as described in connection with Fi 5.The said wipers are now raised to positions level with the sixth rows ofcontacts from below, reference being had to said- Fi 5. The ten sets ofcontacts, comprising this level, are multiple terminals of ten connectorswitches, circuits of one of which I have illustrated nector switchesare assigned for connection to subscribers lines, numbered from 600 to699 inclusive. In its return to normal, dial Z closes contact a singletime between springs 2 and 3 momentaril and a current impulse flows fromground 8, throughcontact 2-3, limb S, 46-47, winding of relay 21 tobattery 33. Relay 21 is energized, attracts its armature, closingcontact momentarily between springs 23 and 24, whereupon current flowsfrom ground G through 23-24, private magnet 29, to battery 33. Saidmagnet is energized and deenergized and sideswitch arms 34, 38, 42 and46, operated by said magnet as previously described, engagerespectively, contact-points 36 40, 44 an 48. Current flows from groundG, through 36-34, secondary magnet 25, contact 26 to battery 33. Magnet25 is energized and then deenergized, it being in vibratory circuit withcontact 26, and wipers 50, 51 and 52 engage the first contacts of theselected levels. If these contacts are idle, arms 34, 38, 42 and 46engage contact-points 37, 41, and 49, respectively, under the influenceof' arm 25, shown and described in connection with Fig. 5. The contacts,terminals of con- .nector switches, are multigled .to other selectorswitches, as indicate in the drawing at 106, 107 and 198, and if thefirst connector switch of the group is already in. use when wiper 50engages contact 106, shown at E, current will flow from ground G ofanother selector switch rendering the connector switch busy, of saidselector switch, its relay 27, its wiper 50 to some multiple contact106', to contact 106, to wiper 50 of selector switch D of the callingsubscriber, through its relay 27, its contact 38-40, through privatemagnet 29, to battery 33. This flow energizes magnet 29 and preventstemporarily the movement of v the side-switch'arms.

The resistances of magnet 29 and relays 27 are so proportioned that thesaid relays 27 do not attract their armatures under Thus, if the'firstset of contacts of the selected levelsis busy, the side-switch armsremain in engagement with their middle contact-points, and secondarymagnet 25 is energized and denergized a second time. This brings wipers50,- 51 and 52 into en agement with a set of contacts, terminals 0 thesecond connector switch of the selected group. If this is at E. Theseconthrough contact 41-38 meaeaa busy, its contact 106 will be groundedat ground G of some other selector switch, circuit will be continuedthrough private magnet 29 of D, the side-switch arms of switch D remainimmovable and secondary magnet 25 is again energized and de'energized,causing the wipers to engage the next contacts. As soon as an idle setis reached, its contact 106 will be insulated from ground G of any otherselector switch, as is apparent from an inspection of E. Current will bebroken through private magnet 29 and, with the retraction of thearmature of secondary magnet 25, arms 34, 38, 42 and 46 engagecontact-points 37, 41, 45 and 49 respectively. The movement of arm 34opens circuit through magnet 25, the wipers 50, 51 and 52 of theselector switch remaining in engagement with the idle connector switchterminals, assumed to be terminals 106, 107 and 108 shown at E. Themovement of arm 38 connects ground G through relay 27 and wiper 50 toterminal 106 of the selected connector switch and its multiples,rendering the connector switch busy. It will be noted that wipers 51 and52, terminals of the line of subscriber A, were dis connected from theline while they were wiping over busy contacts, the movement of arms 42and 46, described as occurring immediately upon the selection of idlecontacts, connecting the said wipers through to the limbs of the line.

It should be noted that arm 17, with the first upward movement of theselector switch shaft, connected ground G to contact 120, a multipleconnector switch terminal of the line of subscriber A, rendering theline busy with respect to calling subscribers desiring connection withit, as will be hereafter described.

Operation of connector switch E .Subscriber A, by rotating and thenreleasing dial Z, now causes two impulses of current to flow from groundG over limb P of the line, through contacts 4245, 51107 (E), relay 104to battery 33, the relay attracting its armature twice, causing twoimpulses of current to flow from ground G through armature of magnet 29through arm 34 primary magnet 31 to battery 33, raising the shaft of theconnector switch two steps upward. Associated with the wipers of thesaid connector switch are one hundred sets of multiple terminals such asshown in Fig. 5, including those of subscribers numbered from 600 to 699inclusive, the lowest rows including those from 610 to 619 inclusive,the second rows those from 620 to 629 inelusive, and so upward, the toprows including those from 600 to 609 inclusive. Thus, the two upwardsteps of the shaft referred to brought wipers 50 51 and 52 level withthe rows of contacts, terminals of lines numbered from 620 to 629inclusive. A

single impulseof current flows from ground Gr, with the return of thedial to normal, through contact 23, limb S, 46-49, 52-408, relay 105 tobattery 33, causing the attraction and release of the relays armatureand a flow of current from ground G through private magnet 29 to battery33. Side-switch arms 38 42 46 and 34 are, with the resultingenergization and deenergiz'ation of magnet 29 ,moved to engage theirintermediate contact-points. Subscriber A, by dial Z, now causes sevenimpulses of current to flow from ground G, over limb P, through relay104 to battery 33, the operation of the relay resulting in sevenimpulses from ground G, through armature of magnet 29 through arm 34through secondary magnet 25 to battery 33. The shaft of the switch isthereby rotated seven steps and, with the seventh step,

its wipers engage contacts, multiple terminals of the line of subscriber627, or subscriber C. This subscriber is provided with a selector switchcircuit, shown at G. Wipers 50 51 and 52 of the connector switch are nowin engagement with contacts 120, 121 and 122 of the called-forsubscribers line, the said contacts having circuit connections as shownat G.

If the called-for line is busy, its contact 120 will be grounded atground G, due to the movement of arm 17 (if a calling line), or atground G of a connector switch (if is be a called-for line). Assumingthat it is busy, a single impulse of current caused to flow from groundG of the substation at A, with the return of the dial to normal, throughcontact 23 and through relay 105, efiects circuit changes as follows:Current flows from ground G", through private manet 29 to battery 33.The said magnet attracts its armature 29 and current flows from groundedcontact 120, through wiper 50 ,through arm 38 to its intermediatecontact-point, through armature 29", through release magnet 32 tobattery 33. The re lease magnet is energized and the connector switchreturns to normal. When, now, subscriber A depresses key 12 for thepurpose of ringing the called subscriber, the shaft of the connectorswitch is stepped upward, just as though a single impulse had been sentover limb P by the dial, contact 12 is closed and subscriber A receives,from busy-back machine118, the busy signal. Subscriber A thereuponreplaces his receiver, arm 13 cooperating with springs 14, 15 and 16 tosimultaneously ground limbs P and S for a moment. Relays 104 and 105 aresimultaneously energized, closing current from scribed.

circuit with low resistance magnet 32 and de'nergized, momentarilyclosing circuit through release magnet 32 and the selector switch is.released and returns to normal. All apparatus is now at normal. Assumingnow that the called line is idle, its contact 120 will be in thecondition shown at G in Fig. 1; and the connector switch is not releasedin the manner described, the release magnet remainin inert, 'but withthe deenergization of private magnet 29 the s1deswitch arms of theconnector switch move to their third positions. Ground Gr is thenconnected to wiper 50 and 120, rendering the called line busy. Alsocurrent flows from said ground G through wiper 50, contact 120,cut-o-fl' relay 18 of the called line, to battery 33, energizingthe'said relay, which opens the circuits of the selector relays 20 and21. Subscriber A now grounds limb P of the line by means of key 12,relay 10.4: is energized, the attraction of whose armature closescircuit from ground G", through ringing relay 117 to battery 33. Theenergization of this relay puts generator 124 into circuit with thecalled, subscribers line and rings his bell. When the called subscriberresponds, conversation proceeds, the conversational circuit being tracedby the heavy lines. When they have finished their conversation, theyreplace their rece1vers. If the called subscriber does this first, hecauses SIIIIUltHIIQOHS-BHGIgIZa'tIOII of relays 101i and 105, thusenergizing release magnet 32, and the connector switch only is released,the other apparatus remaining to be released by the calling subscriberin the manner previously described. If the calling subscriber replaceshis receiver first, both selector switch and connector switch arereleased in the manner previously de- Connection from automaticswitchboard to manual switchboard-I will now describe the method ofoperation whereby the line of subscriber A may be connected forconversation with the line of subscriber B. I have shown a singlelinlccircuit H and a single manual exchange linethat connected withsubstation B. It will, of course, be understood that as many manuallines may be brought to the operators position, whereat circuit Hterminates, as may be desired, subject only to the limitation ofjack-space. As all these lines would have circuits identical with thoseshown, but a single one is illustrated. It will also, of course, beunderstood that as many operators positions will be provided as will berequired to han- (llethe traflic that may exist. Also a plurality oflink-circuits identical with H would, in practice, terminate at eachoperators position, the number depending upon the amount of businesswhich each operator could handle. 'I have shown the link-cir- Vatemagnet becomes energized (altholgh cuit terminals provided with but twosets of multiple contacts 53, 54, 55 and 53', 54 55. Obviously, thenumber of selector switches to which they might be multipled woulddepend upon the business transacted. Obviously, also, the number oflink-circuits accessible to any given line would be determined by thevolume of business originating from the subscribers, and my invention isnot limited to a switch having ten setsof .contacts upon each level.

These general features are collateral to my invention, being matters ofexpediency obvious to those skilled in the art.

Referring to Fig. 1, 53, 54 and 55 are multiple terminals of onelink-circuit extending from bank-contacts of the first selector switchof subscriber A to an operators position at a multiple switchboard, thesaid link-circuit there terminating in a manually operated plug,multiple spring-jacks of subscribers lines being provided for makingconnection with sa1d plug. Contacts 53, 54 and 55 may be located uponthe lowest levels of the selector switch, although, obviously, myinvention is not restricted to such location or the employment of asingle level. If the subscriber, whose line terminates in the automaticswitchboard, de-

sires connection with a subscriber whose line terminates in the manuallyoperated switchboard, he, by sending one im ulse of current from groundG over limb of the line, by rotating his dial, steps the shaft of hisselector switch up one step, bringing the wipers level with contacts,terminals of ten link-circuits of the character described.

These may all lead to one operators position, or may be distributedamong several.

A single impulse from ground at substation A, flowing (on the return ofthe dial to normal) over limb S of the line, energizes and deenergizesprivate magnet 29 as before described, the side-switch arms being causedthereby to assume their .rotary direction, ringing wipers 50,- 51 and 52into engagement with terminals of the first link-circuit of the group.If this is idle, the side-switch arms.

.assume their third positions as before deintermediate posi- .tlons andsecondary magnet 25 ste s the shaft one step in a some other selectorswitch, current will flow from ground G at said other selector switch,through its contact 4138, throu its relay 27, its wiper 50, to amultiple 0 the contact engaged by wiper 50 of the switch of subscriberA, then through relay 27 of said switch, its contact 3840, its privatemagnet 29 to battery 33. In such case, the prirelays 27 do not, aspreviously explain and 52.

pose, the contacts, wiped over by wiper 50,

maybe made wider than the contacts wiped over. by wipers 51 and 52, orthe wiper itself may be made broader than wipers51 As soon as terminalsof an idle link-circuit are reached, circuit is broken through magnet29, and side-switch arms 31, 38, 42 and 16 engage contact-points 37,41,45 and 49 respectively, wipers 50, 51 and ininals of the idlelink-circuit selected, as-.

52 remaining in engagement with the tersumedto be that shown at H inFig. 1. The closing of contact 1138 connects ground G through wiper 50to contact 53 and its multiples, rendering the selected link-circuitbusy with respect to other selector switches having access to multipleterminals of said link-circuit.

It will be noted that wipers 51 and 52 are normally disconnected fromthe limbs and spring-jacks of their associated calling line and remainso disconnected as long as they are wiping over busy contacts. As-soonas idle contacts are reached, the movement of side-switch arms 42 and 46connects them through to the two line limbs and springjacks. SubscriberA may now depress key 12, and current flows from ground G throughcontact 9-8, the receiver being off the hook at this time, over limb P,through contacts 4245, 51-54, over conductor 74, through the left-handwinding of relay (Sheet 2) to battery 33. Relay 60 is energized, closingcircuit through lamp 62 from ground G to battery 33 by the attraction ofits armature 63. Its armature 64 is also attracted, establishing alocking path for the said relay 60 from ground G through normally closedlistening-key contact 83-82, through armature 64; and the right-handwinding of relay 60 to battery 33. The subscriber thus automaticallymakes connection to the first idle linlccircuit H and then lights thesignal-lamp associated with said linkcircuit.

' vers 80 and 81 of her-listening-key, thus bridging her talking-setacross the strands of the link-circuit, and ascertains the numher of thesubscriber wanted. lln throwing over the levers of her listening-key,she opens contact 8382, thus interrupting the locking-circuit describedof relay 60, cansing the relays deenergization and the extinguishment oflamp 62. Having learned the number of the subscriber wanted, theoperator touches tip 89 of the plug of the link-circuit tosleeve-contact 91 of a multiple spring-jack of the called subscribersline. If the line is busy, she receives a click in her telephone, due tothe actuation of test relay 89 occurring in the well-known manner, andnotifies subscriber A, who, by replacing his receiver, simultaneouslyenergizes, for a moment, relays '56 and 57 associated with thelink-circuit H (Sheet 1). The resulting closing of contact 58-59 closescircuit through release relay 27 at the selector switch D, which in turncauses a momentary energization of release magnet 32, upon whosedeenergization the selector switch is restored to its normal position,as previously described. If, however, the called line isfidle, theoperator, in testing, receives no click in her telephone, in which case,knowing that the line is idle, she inserts the plug into thespring-jack, closing contacts 89*92 and 90-91.

When the operator inserts the plug into the spring-jack as abovedescribed, current flows from ground G through the cut-off relay 93,through contact 91-90, through the ringing-key leverto its normallyclosed contact, through relay 71 to battery 7 6. Cutoff relay 93attracts armatures 94 and 95 to close their alternate contacts, cuttinglimbs 96 and 97 of the called line into direct connection with contacts92 and 91 of the spring-jack. The energization of relay 71, resultingfrom the above described flow of current, closes current from ground Gthrough the relay armatures alternate contact, through armature 69 ofrelay 68, through supervisory lamp 67 to battery 33, causing the displayof the said lamp. The energization of relay 71 also closes contact 73,establishing the taking circuit of the tip cord strand. The operator nowrestores her listening-in key and throws over levers 86 and 87 of theringing-key, putting generator 88 into circuit with the line of thecalled subscriber B, causing his bell to ring. While the ringing-keylevers are depressed, cut-off relay 93 of the called subscribers line ismaintained energized by aflow of current from ground G through therelay, contact 9190, ringing-key lever 87, via resistancecoil 87 tobattery 76. Until the called subscriber answers the call by removing hisre-- ing of relay 68, through contact. 73-72 (relay 71) being at thistime energized), ring- -1ng-key lever 86, contact 89-92, armature 94,limb 96, then through the substation, returning over limb 97, througharmature 95, its alternate contact, contact 91-90, windof relay 71 andto battery 76, is estab- 1n lisiedmausing the energization of relay 68and the attraction of its armature 69, which effects the effacement oflamp 67. The two subscribers A and B are now in conversation, thecircuit being traced bythe heavily lined conductors. It will be notedthat in the structure shown in this figure, subscriber A at theautomatic end has his transmitter over limb S, through relay 57, throughrelay 61 to battery 33, causing the energization ofall' four relays.Relays 56 and 57, being simultaneously energized, close contact 58- 59,which efiects the .energization of release relay- 27.- The latterattracts armature 28, closing current from ground G", through saidarmature and release magnet 32 to battery 33, energizing said magnet.When, with the return of the hook-leverto normal at substation A, groundis removed from the two line limbs, contact 58-59 will be broken, relay27 will be denergized, in turn denergizing release magnet 32 lectorswitch returns to normal.

The energization described above of relay 61 establishes a locking-pathfor it from ground G through alternate contact of armature of'relay 71,the front contact of armature 66, winding of relay 61 to battery 33. Theattraction of armature closed a path for current from ground G throughlamp 62 to battery 33, causing the display of the lamp. The two lampsbeing now displayed, the operator knows that disconnection is desiredand removes the plug from the spring-jack, and all apparatusre-.

turns to its normal condition.

The line-circuit associated with substation B' is of a character wellknown in the art which has gone 'into extensive commercial use, anddetailed description of it is therefore unnecessary.

vReferring to Fig. 2, I there show a varying form of link-circuit whichmay be conhe interrupts being connected to ground through coi and these- If the called line is idle, the operator incalled subscriberresponds.

sidered in connection with the selector switch shown in Fig. 1,connected to sub station A. It is assumed that contacts 53, 54 and 55 inFig. 2 are associated with wipers 50, 51 and 52, respectively, of theselector switch shown at D in Fig. 1 and that the said wipers have beenbrought to rest in engagement with the said contact-pieces in the samemanner as that described in connection with Fig. 1, whereby the areplaced in connection with similarly esignated contacts in Fig. 1.

"In considering Fig. 2, it should be superposed upon Sheet 1 of Fig. 1so that contacts 53-, 54 and 55 of Fig. 2 are adjacent to wi ers 50, 51and 52, respectively, of Fig. 1, S eet 1, circ 't D. When, now,subscriber A de- Bs key 12, relay 126 in Fig. 2 is enercurrent flowingfrom ground at the substation to battery 33; the relay attracts itsarmature, operating its associated sprin combination to close circuitfrom groun G, through the left-hand'winding of relay .60, over conductor74" to batte'ry'33. Relay 60 attracts its armatures, illuminating lamp62 and establishing a locking circuit from ground G through itsright-hand winding to battery 76. g The operator, throwi over levers and81, opens the locking circuit, Which results in theextinction ofcall-lamp 62, learns the number of the desired subscriber and tests thecalled-for line by touching tip 89- of the plug to'test-ring 177 of thespring-jack of the line.. If the line is busy, she hears. a click, dueto test-ring 177 180, advises thecalling subscriber, and he, byreplacing his receiver, simultaneously energizes relays 126 and 127,which results in the release of the selectorfi switch, due to theresulting'closure of contact 130-133, which closes circuit from groundG", through relay 27, said contact, resistance 133 to battery 33, saidresistance being relatively low.

serts the plug, closing contact 89-179, the

sleeve 90 of the plug connectin with 178 only. With the insertion of thep ug, circuit is closed from ground G, through cut-ofi relay 180, tobattery 76, the cut-off relay attracting its armatures and extending thecircuits of the line to the spring-jacks. With the energization of relay180, current flows from ground Gr at the substation, over limb 96,-armature of relay 180, through contact '17 9-89, through relay 176, theupper winding of relay175 to battery 76. Relay 176 is energized andattracts its armature to engage the associated alternate contact. Relay175 attracts its armature to close circuit from ground, throu hsignal-lam 67 to battery 76. Lamp 67 remains liglited, except during theringing operation, until the The operator now throws over levers 86 and87, putting memes ringing generatorinto circuit with the calledsubscriber's line. current passing from generator 88, through contact89-479, through armature of relay 180, over limb 96 of the line, throughthebell and to ground G at the substation, ringing the bell. When thesubscriber answers the call, the removal of the receiver operates tobreak the ground connection to limb 96 and closes the metallic circuitof the line through the substation. Current thereupon flows from groundG at the exchange, through the lower winding of relay 175, throughcontact 90 -178, over limb 97*, through the transmitter and receiver atthe substation, returning over limb 96, through contact 179-89, throughrelay 176, the upper winding of relay 175 to battery 76. Relay 175 isdifferentially wound, and, equal current flowing in its two windings,its armature is released and returns to normal, opening circuit throughlamp 67* andextinguishing it. The two subscribers are now inconversation,'the talking circuit being traced by the heavily markedconductors. When, at the end of conversation, subscriber K replaces hisreceiver, limb 96 is connected to ground G and current then flowsthrough the upper winding of relay 175 only, as before described. Ittherefore attracts its armature and illuminates lamp 67 When the callingsubscriber A replaces his receiver, relays 126 and 127 are energized,thus restoring the selector switch as before described, and causing alsothe energization of relay 61 by a flow of current from ground G throughthe left-hand winding of relay 61, closed contact of relay 127, tobattery 33. The energization of relay 61 establishes a locking-circuitextending from ground G through the armature of relay 176 to battery 76.The energization of relay 61, attracting armature 65, closes circuitthrough lamp 62, and the two lamps 62 and 67 being now illumined, theoperator withdraws the plug, deenergizing relay 176,

and all remaining apparatus returns to normal.

Gomzectz'on from an automatic lineman automatic line by means ofmanually 0perated cord circaits.1n Fig. 1, each automatic subscribersline is provided with multiple spring-jacks consisting of contacts 113,114 and 115, connected as shown. For making connection with thesemultiple jacks, are provided plugs with circuits as shown at F. If anautomatic subscriber calls for a line of character similar to his own,by way of circuit H, he tells the operator at H the number of the linedesired, she communicates in the well known manner, by orderwire, withanother operator before whom the plug of circuit F appears and withinwhose reach are multiple jacks of the automatic lines, advising her ofthe line wanted. This second operator tests the called line and, iffound idle, completes the connection, the first operator placing theplug terminal of circuit H in the jack terminal of circuit F.

The multiple spring-jack terminal of circuit F is so connected as togive a test when the plug of circuit F is touched to the jackthimble.This being so, it is possible to allow either operator to determlnewhich one I of a plurality of link-circuits, such as F, is to be used incompleting a given connection. While I have above described thisoperation as employing the services of two operators, it will beunderstood by those skilled in telephony that the multiple spring-j acksof both automatic and manual lines can perfectly Well be within thereach of a single operator, and this operator be provided with plugshaving circuit connections as shown at'H and F. In such case, the entireoperation would be completed by a single operator. The circuits,illustrated in Fig. 1, are pntirely adapted to either method ofoperaion.

Assuming that the plug of circuit H is to be manipulated by one operatorand the plug of circuit F by another operator, and that subscriber A isto be connected with subscriber C by the said circuits, the details ofthe operation are as follows: Subscriber A, having connected his linewith circuit H in the manner previously described, advises the operatorof the number of the line desired. She will, by order-wire, advise theoperator at F of the number of the line wanted. The latter may designatea trunk to be employed and the operator at H will insert the plug of Hinto the spring-jack of the designated trunk assumed to be trunk F.Contacts 8998 and 90-99 are closed thereby and current will flow fromground G through the winding of relay 101, through contact 99-90,ringingkey lever 87, winding of relay 71 to battery 76, energizingrelays 101 and 71. The latter attracts its armatures, closing contact7273, completing the talking-circuit of the tip strand of the cord.Current also flows from ground G at circuit H, through relay 68, contact7372, contact 8998, through impedance 100, armature of relay 100 tobattery 33. Relay 68 is thus energized, preventing the illumination oflamp 67. The operator at F tests by depressing the levers of herlistening-key and touching tip 110 of the plug to sleeve contact 113associated with the called linethat of subscriber C. If this line isidle, contact 113 will be in the condition shownnamely, connected to theactive side of battery 33and has no other ground connection. Tip 110 isat this time, by the depression of the listening-key levers, alsoconnected to the active side of said battery and, there being nodifference of potential between the tip of the plug and the sleevecontact of the jack, the operator receives no click in her telephone.Should, however, the line of subscriber C be busy, sleeve 113 will begrounded at ground G of switch D, or at ground G of a connector switch,if the line of subscriber C is then being employed and aconnection'established by automatic apparatus. Should the plug of an-,circuit F and through the operators receiver. A click is caused,notifying the operator that the line is busy, and she will so advisesubscriber A. She thereupon insorts the plug of circuit F into a specialjack including contacts 113 114 and 115, .in which contacts 114: and 115are dlrectly connected, so as to cause the operation of relay 100*- andtheconsequent display of lamp 67 in link-circuit H, as will appear fromthe subsequent description. Lamp 62 in H Will also be illuminated bysubscriber A hanging up, as previously explained. The

operator at H withdraws the plug. Lamp I 102 at F is displayed, ashereafter described, and the operator at F withdraws the plug from thespecialjack, restoring circuit F to normal.

Should the line tested be found idle, the operator at F inserts the pluginto the spring-jack, thereby closing contacts 110'114, 111-115 and112.113, and restores her listening-key. The closing of the lattercontact causes current to flow from 1 ground, through the said contact,through 1 arm 17 of selector switch G, through cut-ofi' relay 18 tobattery 33, energizing the relay which attracts its armatures to openthe circuits of the selector switch relays. The op.- erator at F nowdepresses the levers of her ringing-key, putting ringing generator 88into circuit with the line of subscriber C,

causing his bell to ring. She thereupon releases the ringing-key and itslevers assume the position shown. When in this position, current flowsfrom ground G through coil 103, through contact 111115, over limb S ofthe line, through. the windings of the bell, through the hooklever atsubstation C, over limb P, through contact 114-110, winding of relay100, to battery 33. Relay 100 attracts its armature to disengage theassociated normal contact, and the circuit before traced, causing theenergization of relay 68 at circuit H, is interrupted, the said relay 68deenergized and its armature retracted to close circuit throughsignal-lamp 67. Relay 71 is at this time energized, and

the lamp 67 willtherefore be displayed and will remain so until thecalled subscriber answers. Thus, the operator at H will know that thecalled subscriber has not responded as long as the lamp remains lighted.When, however, subscriber (J, in response to the call, removes hisreceiver, the hook-lever moves upward, opening the circuit through thebell and closing contact 8-9. The condenser, associated at thesubstation with the receiver circuit, is now interposed in the path ofthe current before described as-energizing relay 100. The said relaytherefore becomes deenergized, its armature again engages its normalcontact, causing a second energization of relay 68 associated withcircuit H. This causes the effacement of lamp 67, and the operator at Hknows that the subscribers are in conversation. Subscribers A and C arenow connected for conversation, the circuit being traced by the heavilymarked conductors, from substation A, through switch D,-link-circuit H,linkcircuit F, to substation C. When they have finished, they replacetheir receivers, subscriber-A causing the illumination of lamp 62 atcircuit H in scribed, and also restoring to normal switch D. SubscriberC, by'replacing his receiver, again establishes the before-traced pathfrom ground G at F, through relay 100", back to battery. The said relayattracts its armature, which results in the denergization of relay 68 atcircuit H and the illumination of the second supervisory signal 67. Thiscircuit relation is the same as that established by the insertion of theplug of F into the special jack, as before mentioned. The operator at H,upon the display of the two signals, withdraws the plug of H from thespring-jack of F, the resulting dcenergization of relay 71 extinguishingboth lamps 62 and 67'. Upon the withdrawal of the plug, relay 101 ofcircuit F is def-Energized and its armature assumes the position shown.The plug of circuit F being still in the jack of line C, relay 100continues energized and signal lamp 102 is now lighted. The operator atF is thereby advised that conversation is finished and withdraws theplug from the spring-jack of the line of subscriber C, which places thecircuits of switch G and circuit F in their normal conditions.

It will be observed. that in the preceding, I have described theoperations as occurring in such order that the operator at F designatedthe trunk to be used. It will be noted that if a plug, belonging to acircuit similar to that shown at H, is inserted in the jack of circuitF,-the sleeve contacts of the multiples of said spring-jack will be at apotential other than earth, due to the Winding of relay 101 beingincluded in circuit. Thus, should the operator at H depress levers 80and 81 of her listening-key the manner'previously deand touch tip 89 tothe sleeve 99 of circuit F, the test-relay 89, associated with heroperators set, will be energized, causing a click in her receiver,advising her that the trunk is busy. Should, however, circuit F be idle,there will be no effective difference of potential, relay 101 and thetest-relay being both connected to ground, no click will be heard andthe operator will know that the trunk is idle. It is this feature of thestructure that renders it feasible to have either operator designate atrunk to be employed and also renders it possible to have a singleoperator complete the whole operation above detailed by a suitablearrangement of apparatus, without any change in the circuits whatever.

Connection from manual lines to automatic lines: In Fig. l, I have notshown the cord-circuit adapted to be used for interconnecting two linesof the character of the line of subscriber B. Such cord-circuits arewell known in the art, such a structure being disclosed in Fig. 2 ofpatent of H. G. VVebster, Telephone Exchange, #795,872, patented August1, 1905.

If subscriber B should desire connection with an automatic line, he, byremoving his receiver, would cause the display of the signal of hisline. An operator would respond by inserting the answering-plug of acordoircuit, such as that specified above, into his answering-jack; andhaving learned the number of the subscriber wanted, the opera tor wouldinsert the calling-plug of the said cord into a spring-jack of a circuitsuch as F. The detail of the operation from this point will be the sameas that outlined in the preceding description, inasmuch as the circuitconnections and method of operation of the calling-end of thecord-circuit, above referred to, are substantially identical with thoseof the plug or circuit H.

Connection from an automatic line to an automatic line by a singlemanually oper* ated cord connector: Should it be desired to have asingle telephone operator regularly complete connections in largenumbers between automatic lines by employing plugs and using them toconnect with spring-jacks of such lines, it would be preferable that theoperator use a single plug in making such connections, rather than twoplugs as mentioned above.

In Fig. 3, I have illustrated an obvious modification of circuits H andF of Fig. 1, whereby calls between automatic subscribers may becompleted by manual means, a single operator and a single plug, maniplated by her, being employed. In the said Fig. 3, I have combined oradded together circuits F and H, omitting such apparatus as would besuperfluous where one operator only-is employed. This circuit is adaptedfor trunking between exchanges, or may be employed in a single exchange,the automatic lines having their multiple spring-jacks, shown in Fig. 1,appear before operators provided with the link-circuits, as shown'inFig. 3. In case a subscriber found himself unable to complete a call bythe automatic apparatus, he would automatically connect his line to afirst idle link-circuit and secure the aid of the operator to completethe call, or report trouble.

In considering Fig. 3, it should be placed upon sheet Z in such a mannerthat its contacts 53, 54 and 55 will be practically superposed uponsimilarly designated contacts of circuit I-I. Contacts, formingterminals of circuits such as are shown in Fig. 3, may take the place ofcontacts forming terminals of circuits such as are shown at H, on thelowest levels of the selector switches, or they may be upon any desiredlevel or levels The selections of a first idle circuit, such as it shownin Fig. 3, by subscriber A, will be accomplished in the same manner asthat described in connection with circuit H. Assuming that the wipers ofselector switch D have come to engagement with contacts 53, 54 and 55 ofFig. 3, lamp 62 is displayed as before described. The operator, throwingover levers 80 and 81 of her listeningkey, ascertains the number of theline desired, by the same act retiring lamp 62, as before described.Associated with the plug of Fig. 3, are shown spring-jacks which are themultiple spring-jacks of the line of subscriber C, shown in Fig. l. Theoperator will now test the line wanted, as described in connection withcircuit F. The line being assumed idle, the operator inserts the plug,and current flows from ground G of Fig. 3, through relay 112 throughcontact 112 413, through the cut-off relay 18 of the selector switch ofthe called line, energizing it as before described, to battery 33. Relay112" will remain energized as long as the plug is in the jack. Havingrestored her listeningkey, the operator throws over levers 86 and 87' ofher ringing-key, causing the bell of the called subscriber to ring, andrestores the levers as before described. Current then flows from groundG through coil 103*, through contact 11l -1l5 over limb S of the calledline, through the bell and hook-lever, returning over limb P, throughcontact 114-410 and relay 100, to battery, as previously described.Relay 1.00 attracts its armature to close circuit through signal lamp102, which remains lighted until the subscriber removes his receiverlVhen this by the called subscriber, of his receiver, reestablishescircuit through relay 100, causing the display of the associated lamp102", as before described. When subscriber A replaces his receiver, heenergizes s1mu1- taneously relays 56 and 57, releasing the selectorswitch. The flow from ground at the substation, through, relay 57 alsopasses through the left-hand winding of relay 61,

to battery 33, energizing the relay, which, by attracting its left-handarmature, effects the display of lamp 62 all as prev ously explained.The attraction of its right-hand armature closes a locking-circuit forthe relay from ground G the armature of relay 112", its alternatecontact, through the right-hand winding of relay 61, to battery. Bothsignals being displayed, the operator withdraws the plug, opening c1rcu1t through relay 100, whose 'deenergizatlon puts out lamp 102'. Thewithdrawal of the plug also opens the circuit of relay-112",

whose armature thereupon disengages its alternate contact, openingcircuit through relay 61, whose armatures return to normal, putting outlamp 62. All apparatus is now restored to normal.

A that all connections are to be established by the automatic selectionof manually operated link-circuits, it is obvious that the primary orvertical step-bystep motion of the automatic switch may be dispensedwith, retaining only the secondary or'rotary step-by-step mechanlsm, bymeans of which the automatic selection of afirst idle link-circuit maybesecured, as heretofore described.

In Fig. 4, I have illustrated this employment of my invention. Inconnection with Fig. 4, a mechanical switch, identical with thatillustrated in Figs. 5-9, may be employed, with the exception that thepawl 31, associated with the armature of primary magnet 31, is omittedand that wipers 50, 51 and 52 are'normally in line with the contacts tobe selected, which may be the lowest contact-levels shown in Fig. 5.This change in position is indicated in Fig. '10. The contact-levels ofthe switch shown in Fig. 5, other than the lowest, are not used inconnection with Fig. 4 and may be left disconnected. Spring 17, Fig. 11,is caused to be connected to ground G with the first rotary movement ofthe shaft, a simple way of accomplishing this being shown in said Fig.11.

Referring to the circuit drawing, Fig. 4, I there show substationcircuit A, connected by its telephone'line with the circuits of theautomatic switch D at the exchange.

The substation mechanism. is the same as that previously described inconnection with the automatic lines, except that I prefer to send theimpulses required to start the sel5 lection of the first idle cord, bythe removal circuit D.

of the telephone from its hook. To this end, I provide, in Fig. 4, aspring-lever 8", associated with the switch-hook and normally engaging apin 8 upon dial 1. When the telephone is removed from the hook, saidlever causes the rotation of the dial in the same manner as though itwere manually operated to send one primary and one secondary impulseupon its release, which is secured by the automatic disengagement oflever 8? from pin 8 by the stationary pin 8 operating upon the lever 8as the hooklever closes its alternate contacts.

The switching mechanism associated with the line at the central oflicetherefore receives the same impulses, as previously described inconnection with circuit H in this case, when the subscriber initiates acall by removing hisreoeiver.

Obviously, my invention is not limited to such an automatic transmissionof the required impulses, but includes also the manually actuated dialpreviously described. The circuit arrangement, "shown at D, is identicalwith that shown at D, although the selector switch mechanism is nowprevented from making its vertical movement. The removal, by thesubscriber at A, of his receiver, therefore automatically secures theselection of the first idle link-circuit terminating before someoperator, as before described.

At C, I have shown another substation similar to A, connected with thelimbs of the telephone line to a switch circuit G G at the exchange,similar in all respects to The cord connector, shown at I in3Fig. 4, isthe same as that shown in In the exchange-system comprised in Fig. 4,each subscribers line terminates at the exchange in an automatic switchhaving circuits similarto D and G G; said circuits being the same as theselector circuits of Fig. 1. In addition to being connected with theswitch circuit, each subscribers line, as

before described, is provided with multiple sprmgqacks, appearing beforethe various operators at the switchboard, in the well a known manner.

In Fig. 10, I have shown a level of contacts, comprising ten sets.Obviously, the wipers of each subscribers switch may, if it is founddesirable, have more than ten sets of cord circuit terminals adapted tobe engaged or selected by them. In practice, the number provided wouldbe determined by considerations of expediency and expense. The cordcircuits, leading from one sub scribers switch, may all terminate at oneoperators position, or they may be divided a part leading to oneposition, and a part to another.

The operation of the system, shown in Fig. 4, will be obvious from thedescription tlllli moss already given of Fig. 3, it being the same.Moreover. it is apparent that the size of the groups of lines, and thenumber of linkcircuits allotted to each group of lines, would bedetermined by considerations of expediency, it being now apparent thatas many link-circuit connecting terminals, as expediency may determinewould be provided in the single selecting level shown in Fig. 10.

It is apparent that my invention is not limited to any particulargrouping of lines and allotted link-circuits, but that many otherobvious groupings of the link-circuits before the various operators maybe employed. Moreover, it is apparent that my invention is not limitedto the single level of automatically selected idle link-circuits,illustrated in Fig. 10, but I contemplate also the manual selection bythe subscribers of particular levels provided with link-circuitterminals leading to various divisions of the same exchange switchboard,or to a plurality of switchboards.

lit will be obvious that my invention is applicable to many othertelephone exchange systems in which it is desirable that the subscribershall cause an automatic selection of a first idle cord-circuit of agroup of cords available for his service, and that my invention is notlimited to the particular applications described and shown in thisspecification, but

What I claim as my invention is 1. A telephone exchange systemcomprising a plurality of telephone lines provided with spring-jacks atthe exchange, selective switches for said telephone lines, groups oftrunk lines adapted to be selected by said selective switches, auxiliaryselective switches for certain of said trunk lines adapted to beoperated in completing connections with desired lines, manually operatedlink-circuit terminals for others of said trunk lines adapted to be usedin completing connections with spring-jacks of desired lines, stationarycontacts for said first switches, forming terminals of said trunk lines,selecting contacts for said first switches normally disconnected fromsaid lines, means for rendering said trunk lines busy when in use, meansfor automatically moving said selecting contacts, while disconnectedfrom said telephone lines, over the stationary contacts of said trunklines, calling devices for said telephone lines at the substations forcontrolling election of said groups of trunk lines, other telephonelines provided with spring-jacks, means for causing said selectingcontacts to select the first idle trunk line, provided with a manuallyoperated terminal, and connect its associated line thereto, and meansfor restoring to normal said first selective switches at the con clusionof conversation.

2. A telephone exchange system comprising a plurality of telephone linesprovided with spring-jacks at the exchange, selective switches for saidtelephone lines, groups of trunk lines adapted to be selected by saidselective switches, auxiliary selective switches for certain of saidtrunk lines adapted to be operated in completing connections withdesired lines, manually operated link-circuit terminals for others ofsaid trunk lines adapted to be used in completing connections withspring-jacks of desired lines, stationary contacts for said firstswitches, forming terminals of said trunk lines, selecting contacts forsaid first switches normally disconnected from said lines, means forrendering said trunk lines busy when in use, means for automaticallymoving said selecting contacts, while disconnected from said telephonelines, over the stationary contacts of said trunk lines, calling devicesfor said telephone lines at the substations for controlling election ofsaid groups of trunk lines, other telephone lines provided withspring-jacks, means for causing said selecting contacts to select thefirst idle trunk line, provided with a manually operated terminal, andconnect its associated line thereto, means for restoring to normal saidfirst selective switches at the conclusion of conversation, and callingsignals associated with said trunk-circuits provided with said manuallyoperated terminals to indicate when connection is made with an idle onethereof.

7 3. A telephone exchange system comprising a plurality of telephonelines provided with spring-jacks at the exchange, selective switches forsaid telephone lines, groups of trunk lines adapted to be selected bysaid selective switches, auxiliary selective switches for certain ofsaid trunk lines adapted to be operated in completing connections withdesired lines, manually operated link-circuit terminals for others ofsaid trunk lines adapted to be used in completing connections withspring-jacks of desired lines, stationary contacts for said firstswitches, forming terminals of said trunk lines, selecting contacts forsaid first switches normally disconnected from said lines, means forrendering said trunk lines busy when in use, means for automaticallymoving said selecting contacts, while disconnected from said telephonelines, over the stationary contacts of said trunk lines, calling devicesfor said telephone lines at the substations for controlling election ofsaid groups of trunk lines, other telephone lines provided withspring-jacks, means for causing said selecting contacts to select thefirst idle trunk line, provided with a manually operated terminal, a andconnect its asso-' ciated line thereto, means for restoring to normalsaid first selective switches at the conclusion of conversation, callingsignals associated with said trunk-circuits provided with said manuallyoperated terminals to indicate when connection is made with an idle onethereof, and supervisory signals associated with saidmanually operatedterminals adapted to, indicate the condition of the called subscrih rsline.

4. A telephone exchange system comprising a plurality of telephone linesprovided with spring-jacks at the exchange, selective switches for saidtelephone lines, groups of trunk lines adapted to be selected by saidselective switches, auxiliary selective switches for certain of saidtrunk lines adapted to be operated in completing connections withdesired lines, manually operated link circuit terminals for others ofsaid trunk lines adapted to be used in completing connections withspring-jacks of desired lines, stationary contacts for said firstswitches, forming terminals of said trunk lines. selecting contacts forsaid first switches normally disconnected from said lines, means forrendering said trunk lines busy when in use, means for automaticallymoving said selecting contacts, while disconnected from said telephonelines, over the stationary contacts of said trunk lines, calling devicesfor said telephonelines at the substations for controlling. election ofsaid groups of trunk lines, other telephone lines provided withspring-jacks, means for causing-saidselecting contacts to select thefirst idle trunk line, provided with a manually operated terminal, andconnect its associated line thereto,

means for restoring to normal said first selective switches at theconclusion of conversation, calling signals associated with saidtrunk-circuits provided with said manually operated terminals toindicate when connection is made with an idle one thereof, andsupervisory apparatus associated with said manually operated terminalsadapted to indicate the condition of each connected subscribersline.

5. A telephone exchange system comprising a plurality of telephone linesprovided with spring-jacks at tive switches for saidtelephone lines,groups of trunk lines adapted to be selected by said selective switches,auxiliary selective switches for certain of said trimk lines adapted tobe operated in completin connections with desired lines, manna yoperated link-circuit terminals for others of said trunk lines adaptedto be used in completing connections with spring-jacks of desired lines,stationary contacts for said first switches, forming terminals of saidtrunk lines, selecting contacts for said first switches normallydisconnected from said lines, means for rendering said trunk-lines busywhen in use, means for automatically moving said selectin contacts,while disconnected from said te ephone lines, over the stathe exchange,selec-.

minals adapted to indicate the condition of each connected subscribersline.

6. In a telephone system, a switchboard, a subscribers telephone line, aselective switch for said line, selecting contacts for said switchnormally disconnected from said line, waiting contacts for saidselecting switch, trunk lines leading from said waiting contacts to saidswitchboard, means outside of said switch for rendering some of saidtrunk lines busy, means for automatically moving said selecting contactsover the waiting contacts of said busy trunks while said selectingcontacts are disconnected from said subscribers line, other telephonelines, multiple jacks in said switchboard pertaining to said othertelephone lines, connecting means in said switchboard whereby any trunkmay be connected to a multiple ack of a selectedline, and a trunkrelease circuit for said selective switch extending through its testWiper for restoringsaid. switch to normal at the end of conversation.

7. 'In a telephone system, a switchboard, a subscribers telephone line,a selective switch provided with release mechanism for said line,selecting contacts for said switch normally disconnected from said line,waiting contacts for said selecting switch, trunk lines leading fromsaid waiting contacts to said switchboard, means outside of said switchfor rendering some of said trunk lines busy, means for automaticallymoving said selecting contacts over the waiting contacts of said busytrunks while said selecting contacts are disconnected from saidsubscribers line, other telephone lines, multiple jacks in saidswitchboard adapted to complete connection to said telephone line,multiple jacks in saidswitchboard pertaining to said other telephonelines, connecting means in said switchboard whereby any trunk may beconnected to a multiple jack of a selected line, and a trunk releasecircuit for controlling said release mechanism extending through thetest wiper of said selective switch. 7

8. In a telephone system, a switchboard, a subscribers telephone line, aselective switch provided with release mechanism for said line,selecting contacts for said' switch normally disconnected from saidline, waiting contacts for said selecting switch, trunk lines leadingfrom said waiting contacts to said switchboard, means outside of saidswitch for rendering some of said trunk lines busy, means forautomatically moving said selecting contacts over the waiting contactsof said busy trunks while said selecting contacts are disconnected fromsaid subscriber's line, other telephone lines. multiple jacks in saidswitchboard pertaining to'said telephone line, multiple jacks in saidswitchboard pertaining to said other telephone lines, connecting meansin saidswitchboard whereby any trunk may be connected to a multiple jackof a selected line, and a trunk release circuit for controlling saidrelease mechanism extending through the test wiper of said selectiveswitch.

9. In a telephone system. subscribers telephone lines, selectiveswitches associated therewith, a multiple switchboard-having a pluralityof operators positions, selecting contacts for said selective switchesnormally disconnected from said lines, stationary contacts for saidselective switches, a series of trunk lines leading from said stationarycontacts to SGYQItll of the positions on said multiple switchboard,means for causing a selective svitch to automatically move its selectingc ntacts into engagement with the stationary contacts of the first idletrunk line of its series, means for simultaneously connecting saidselecting contacts with the associated subscribers lines, and trunkrelease circuits for said selective switches ex tending through theirtest wipers for restoring said switches to normal at the end ofconversation.

10. In a telephone system, a subscribers line, a multiple switchboard inwhich said subscribers line terminates, a selecting switch for saidline, movable contacts upon said switch normally disconnected from saidline, stationary contacts for said selecting switch, means under thecontrol of the subscribers line for causing said movable contacts toengage certain of said stationary contacts and to simultaneously connectsaid line to said selecting contacts, other subscribers linesterminating in said multi-' ple switchboard. trunks extending from saidstationary contacts to said multiple switchboard, switching means insaid switchboard whereby any trunk may be connected with any line,calling signals for said trunks to indicate when a connection is madetherewith, and a trunk release circuit for said selective switchextending'through its test wiper for restoring said switch to normal atthe end of conversation.

11. In a telephone system, subscribers telephone lines, selectiveswitches associated therewith, a multiple switchboard having a pluralityof operators positions, selecting contacts 'for said selective switchesnormally disconnected from said lines, stationary contacts for saidselective switches, a series of trunk lines leading from said stationarycon tacts to several of the positions on said multiple switchboard,means for causing a selective switch to automatically move its selectingcontacts into engagement with the stationary contacts of the first idletrunk line of its series, means for simultaneously connectingsaid'selecting contacts with the associated subscribers lines, trunkrelease circuit for said connected selective switch including its testwiper and a test-contact of the trunk line for restoring said switch tonormal and calling signals for said trunk lines to indicate when aconnection is made to an idle one thereof.

12. In a telephone system, a subscribers line, a multiple switchboard inwhich said subscribers line terminates, a selecting switch provided withrelease means for said line, movable contacts upon said switch normallydisconnected from said line, stationary contacts for said selectingswitch, means under the control of the subscribers line for causing saidmovable contacts to engage certain of said stationary contacts and tosimultaneously connect said line to said selecting contacts, othersubscribers lines terminating in said multiple switchboard, trunksextending from said stationary contacts to said multiple switchboard,switching means in said switchboard whereby any trunk may be connectedwith any line, calling signals for said trunks to indicate when aconnection is made therewith supervisory signals associated with saidtrunks adapted to indicate the condition of a called subscribers line,and a. trunk release circuit for controlling said release meansextending through the test wiper of said automatic switch.

13. In a telephone system, subscribers telephone lines, selectiveswitches associated therewith, a multiple switchboard having a pluralityof operators positions, selecting contacts for said selective switchesnormally disconnected from said lines, stationary contacts for saidselective switches, a series of trunk lines leading from said stationarycon tacts to several of the positions on said multiple switchboard,means for causinga selective switch to automatically move its selectingcontacts into engagement with the stationary contacts of the first idletrunk line of its series, means for simultaneously connecting saidselecting contacts with the associated subscribers lines, callingsignals for said trunk lines to indicate when a con nection is made toan idle one thereof, supervisory signals associated with said trunksadapted to indicate the condition of a called subscribers line, andtrunk release circuits for said selective switches extending throughtheir test wipers for restoring said switches to normal at the end ofconversation.

